/**
 * Knob - jQuery Plugin
 * Downward compatible, touchable dial
 *
 * Version: 1.1.2 (22/05/2012)
 * Requires: jQuery v1.7+
 *
 * Copyright (c) 2011 Anthony Terrien
 * Under MIT and GPL licenses:
 *  http://www.opensource.org/licenses/mit-license.php
 *  http://www.gnu.org/licenses/gpl.html
 *
 * Thanks to vor, eskimoblood, spiffistan
 */
$(function() {

    // Dial logic
    var Dial = function(c, opt) {

        var v = null,
            ctx = c[0].getContext("2d"),
            PI2 = 2 * Math.PI,
            mx, my, x, y, self = this;

        this.onChange = function() {};
        this.onCancel = function() {};
        this.onRelease = function() {};

        this.val = function(nv) {
            if (null != nv) {
                opt.stopper && (nv = Math.max(Math.min(nv, opt.max), opt.min));
                v = nv;
                this.onChange(nv);
                if (opt.dynamicDraw) this.dynamicDraw(nv);
                else this.draw(nv);
            } else {
                var b, a;
                b = a = Math.atan2(mx - x, -(my - y - opt.width / 2)) - opt.angleOffset;
                (a < 0) && (b = a + PI2);
                nv = Math.round(b * (opt.max - opt.min) / PI2) + opt.min;
                return (nv > opt.max) ? opt.max : nv;
            }
        };

        this.change = function(nv) {
            opt.stopper && (nv = Math.max(Math.min(nv, opt.max), opt.min));
            this.onChange(nv);
            this.draw(nv);
        };

        this.angle = function(nv) {
            return (nv - opt.min) * PI2 / (opt.max - opt.min);
        };

        this.draw = function(nv) {

            var a = this.angle(nv) // Angle
                ,
                sa = 1.5 * Math.PI + opt.angleOffset // Previous start angle
                ,
                sat = sa // Start angle
                ,
                ea = sa + this.angle(v) // Previous end angle
                ,
                eat = sat + a // End angle
                ,
                r = opt.width / 2 // Radius
                ,
                lw = r * opt.thickness // Line width
                ,
                cgcolor = Dial.getCgColor(opt.cgColor),
                tick;

            ctx.clearRect(0, 0, opt.width, opt.width);
            ctx.lineWidth = lw;

            // Hook draw
            if (opt.draw(a, v, opt, ctx)) {
                return;
            }

            for (tick = 0; tick < opt.ticks; tick++) {

                ctx.beginPath();

                if (a > (((2 * Math.PI) / opt.ticks) * tick) && opt.tickColorizeValues) {
                    ctx.strokeStyle = opt.fgColor;
                } else {
                    ctx.strokeStyle = opt.tickColor;
                }

                var tick_sa = (((2 * Math.PI) / opt.ticks) * tick) - (0.5 * Math.PI);
                ctx.arc(r, r, r - lw - opt.tickLength, tick_sa, tick_sa + opt.tickWidth, false);
                ctx.stroke();
            }

            opt.cursor && (sa = ea - 0.3) && (ea = ea + 0.3) && (sat = eat - 0.3) && (eat = eat + 0.3);

            switch (opt.skin) {

                case 'default':

                    ctx.beginPath();
                    ctx.strokeStyle = opt.bgColor;
                    ctx.arc(r, r, r - lw / 2, 0, PI2, true);
                    ctx.stroke();

                    if (opt.displayPrevious) {
                        ctx.beginPath();
                        ctx.strokeStyle = (v == nv) ? opt.fgColor : cgcolor;
                        ctx.arc(r, r, r - lw / 2, sa, ea, false);
                        ctx.stroke();
                    }

                    ctx.beginPath();
                    ctx.strokeStyle = opt.fgColor;
                    ctx.arc(r, r, r - lw / 2, sat, eat, false);
                    ctx.stroke();

                    break;

                case 'tron':

                    if (opt.displayPrevious) {
                        ctx.beginPath();
                        ctx.strokeStyle = (v == nv) ? opt.fgColor : cgcolor;
                        ctx.arc(r, r, r - lw, sa, ea, false);
                        ctx.stroke();
                    }

                    ctx.beginPath();
                    ctx.strokeStyle = opt.fgColor;
                    ctx.arc(r, r, r - lw, sat, eat, false);
                    ctx.stroke();

                    ctx.lineWidth = 2;
                    ctx.beginPath();
                    ctx.strokeStyle = opt.fgColor;
                    ctx.arc(r, r, r - lw + 1 + lw * 2 / 3, 0, 2 * Math.PI, false);
                    ctx.stroke();

                    break;
            }
        };

        var dynamicDrawIndex;
        var dynamicDrawInterval;
        this.dynamicDraw = function(nv) {
            var instanceOfThis = this;
            dynamicDrawIndex = opt.min;
            dynamicDrawInterval = setInterval(function() {
                instanceOfThis.animateDraw(nv);
            }, 20);
        };

        this.animateDraw = function() {
            if (dynamicDrawIndex > v) {
                clearInterval(dynamicDrawInterval);
                v = dynamicDrawIndex;
            } else {
                this.draw(dynamicDrawIndex);
                this.change(dynamicDrawIndex);
                dynamicDrawIndex++;
            }
        };

        this.capture = function(e) {
            switch (e.type) {
                case 'mousemove':
                case 'mousedown':
                    mx = e.pageX;
                    my = e.pageY;
                    break;
                case 'touchmove':
                case 'touchstart':
                    mx = e.originalEvent.touches[0].pageX;
                    my = e.originalEvent.touches[0].pageY;
                    break;
            }
            this.change(this.val());
        };

        this.cancel = function() {
            self.val(v);
            self.onCancel();
        };

        this.startDrag = function(e) {

            var p = c.offset(),
                $doc = $(document);

            x = p.left + (opt.width / 2);
            y = p.top;

            this.capture(e);

            // Listen mouse and touch events
            $doc.bind(
                "mousemove.dial touchmove.dial", function(e) {
                    self.capture(e);
                }
            )
                .bind(
                    // Escape
                    "keyup.dial", function(e) {
                        if (e.keyCode === 27) {
                            $doc.unbind("mouseup.dial mousemove.dial keyup.dial");
                            self.cancel();
                        }
                    }
            )
                .bind(
                    "mouseup.dial touchend.dial", function(e) {
                        $doc.unbind('mousemove.dial touchmove.dial mouseup.dial touchend.dial keyup.dial');
                        self.val(self.val());
                        self.onRelease(v);
                    }
            );
        };
    };

    // Dial static func
    Dial.getCgColor = function(h) {
        h = h.substring(1, 7);
        var rgb = [parseInt(h.substring(0, 2), 16), parseInt(h.substring(2, 4), 16), parseInt(h.substring(4, 6), 16)];
        return "rgba(" + rgb[0] + "," + rgb[1] + "," + rgb[2] + ",.5)";
    };

    // jQuery plugin
    $.fn.knob = $.fn.dial = function(gopt) {

        return this.each(

            function() {

                var $this = $(this),
                    opt;

                if ($this.data('dialed')) {
                    return $this;
                }
                $this.data('dialed', true);

                opt = $.extend({
                    // Config
                    'min': $this.data('min') || 0,
                    'max': $this.data('max') || 100,
                    'stopper': true,
                    'readOnly': $this.data('readonly')

                    // UI
                    ,
                    'cursor': $this.data('cursor'),
                    'thickness': $this.data('thickness') || 0.35,
                    'width': $this.data('width') || 200,
                    'displayInput': $this.data('displayinput') == null || $this.data('displayinput'),
                    'displayPrevious': $this.data('displayprevious'),
                    'fgColor': $this.data('fgcolor') || '#87CEEB',
                    'cgColor': $this.data('cgcolor') || $this.data('fgcolor') || '#87CEEB',
                    'bgColor': $this.data('bgcolor') || '#EEEEEE',
                    'tickColor': $this.data('tickColor') || $this.data('fgcolor') || '#DDDDDD',
                    'ticks': $this.data('ticks') || 0,
                    'tickLength': $this.data('tickLength') || 0,
                    'tickWidth': $this.data('tickWidth') || 0.02,
                    'tickColorizeValues': $this.data('tickColorizeValues') || true,
                    'skin': $this.data('skin') || 'default',
                    'angleOffset': degreeToRadians($this.data('angleoffset')),
                    'dynamicDraw': $this.data('dynamicdraw') || false

                    // Hooks
                    ,
                    'draw':
                    /**
                     * @param int a angle
                     * @param int v current value
                     * @param array opt plugin options
                     * @param context ctx Canvas context 2d
                     * @return bool true:bypass default draw methode
                     */

                    function(a, v, opt, ctx) {},
                    'change':
                    /**
                     * @param int v Current value
                     */

                    function(v) {},
                    'release':
                    /**
                     * @param int v Current value
                     * @param jQuery ipt Input
                     */

                    function(v, ipt) {}
                }, gopt);

                var c = $('<canvas width="' + opt.width + '" height="' + opt.width + '"></canvas>'),
                    wd = $('<div style=width:' + opt.width + 'px;display:inline;"></div>'),
                    k, vl = $this.val(),
                    initStyle = function() {
                        opt.displayInput && $this.css({
                            'width': opt.width / 2 + 'px',
                            'position': 'absolute',
                            'margin-top': (opt.width * 5 / 14) + 'px',
                            'margin-left': '-' + (opt.width * 3 / 4) + 'px',
                            'font-size': (opt.width / 4) + 'px',
                            'border': 'none',
                            'background': 'none',
                            'font-family': 'Arial',
                            'font-weight': 'bold',
                            'text-align': 'center',
                            'color': opt.fgColor,
                            'padding': '0px',
                            '-webkit-appearance': 'none'
                        }) || $this.css({
                            'width': '0px',
                            'visibility': 'hidden'
                        });
                    };

                // Canvas insert
                $this.wrap(wd).before(c);

                initStyle();

                // Invoke dial logic
                k = new Dial(c, opt);
                vl || (vl = opt.min);
                $this.val(vl);
                k.val(vl);

                k.onRelease = function(v) {
                    opt.release(v, $this);
                };
                k.onChange = function(v) {
                    $this.val(v);
                    opt.change(v);
                };

                // bind change on input
                $this.bind(
                    'change', function(e) {
                        k.val($this.val());
                    }
                );

                if (!opt.readOnly) {

                    // canvas
                    c.bind(
                        "mousedown touchstart", function(e) {
                            e.preventDefault();
                            k.startDrag(e);
                        }
                    )
                        .bind(
                            "mousewheel DOMMouseScroll", mw = function(e) {
                                e.preventDefault();
                                var ori = e.originalEvent,
                                    deltaX = ori.detail || ori.wheelDeltaX,
                                    deltaY = ori.detail || ori.wheelDeltaY,
                                    val = parseInt($this.val()) + (deltaX > 0 || deltaY > 0 ? 1 : deltaX < 0 || deltaY < 0 ? -1 : 0);
                                k.val(val);
                            }
                    );

                    // input
                    var kval, val, to, m = 1,
                        kv = {
                            37: -1,
                            38: 1,
                            39: 1,
                            40: -1
                        };
                    $this
                        .bind(
                            "configure", function(e, aconf) {
                                var kconf;
                                for (kconf in aconf) {
                                    opt[kconf] = aconf[kconf];
                                }
                                initStyle();
                                k.val($this.val());
                            }
                    )
                        .bind(
                            "keydown", function(e) {
                                var kc = e.keyCode;
                                if (kc >= 96 && kc <= 105) kc -= 48; //numpad
                                kval = parseInt(String.fromCharCode(kc));

                                if (isNaN(kval)) {

                                    (kc !== 13) // enter
                                    && (kc !== 8) // bs
                                    && (kc !== 9) // tab
                                    && (kc !== 189) // -
                                    && e.preventDefault();

                                    // arrows
                                    if ($.inArray(kc, [37, 38, 39, 40]) > -1) {
                                        k.change(parseInt($this.val()) + kv[kc] * m);

                                        // long time keydown speed-up
                                        to = window.setTimeout(
                                            function() {
                                                m < 20 && m++;
                                            }, 50
                                        );

                                        e.preventDefault();
                                    }
                                }
                            }
                    )
                        .bind(
                            "keyup", function(e) {
                                if (isNaN(kval)) {
                                    if (to) {
                                        window.clearTimeout(to);
                                        to = null;
                                        m = 1;
                                        k.val($this.val());
                                        k.onRelease($this.val(), $this);
                                    } else {
                                        // enter
                                        (e.keyCode === 13) && k.onRelease($this.val(), $this);
                                    }
                                } else {
                                    // kval postcond
                                    ($this.val() > opt.max && $this.val(opt.max)) || ($this.val() < opt.min && $this.val(opt.min));
                                }

                            }
                    )
                        .bind(
                            "mousewheel DOMMouseScroll", mw
                    );
                } else {
                    $this.attr('readonly', 'readonly');
                }
            }
        ).parent();
    };

    function degreeToRadians(angle) {
        return $.isNumeric(angle) ? angle * Math.PI / 180 : 0;
    }
});
